This invention relates in general to vehicular brake systems, and in particular is concerned with a control valve mounted in a hydraulic control unit of an electronically controlled brake system.
Electronically-controlled brake systems for vehicles are well known. One type of electronically-controlled brake system includes a hydraulic control unit (HCU) connected in fluid communication between a master cylinder and a plurality of wheel brakes. The HCU includes a housing containing control valves and other components for selectively controlling hydraulic brake pressure at the wheel brakes.
Control valves for HCU""s are commonly formed as electronically actuated solenoid valves. A typical solenoid valve includes a cylindrical armature slidably received in a sleeve or flux tube for movement relative to a valve seat. A spring is used to bias the armature in an open or closed position, thereby permitting or blocking fluid flow through the valve, respectively. A coil assembly is provided about the sleeve. When the valve is energized, an electromagnetic field or flux generated by the coil assembly slides the armature from the biased open or closed position to a closed or open position, respectively.
Control valves mounted in a HCU are actuated by an electronic control module to provide desired braking functions such as anti-lock braking, traction control, and vehicl e stability control.
To provide desired braking responses, an armature must respond quickly and in a predictable manner to an electromagnetic field generated by an energized coil assembly.
This invention relates to a control valve mounted in a hydraulic control unit of a vehicular brake system. The control valve includes a reduced seat formed on an outer surface of a valve seat. The control valve delivers consistent operation under a range of temperatures. Furthermore, fluid flowing through the control valve produces less noise.
In a preferred embodiment, a control valve for controlling fluid flow in a hydraulic control unit of a vehicular brake system includes a valve seat having a longitudinal fluid passage terminating in an opening. The valve seat also includes a planar seat formed on an outer surface of a terminus of the valve seat. The opening is formed in the seat. A sloping surface surrounds the seat. An angle is formed between a line coplanar with the seat and the sloping surface. The angle ranges between approximately 3.5 degrees and 4.5 degrees. A sleeve is mounted on the valve seat. An armature is slidably received in the sleeve.
This control valve is particularly adapted to be mounted in a bore of a housing of a hydraulic control unit of an electronically controlled vehicular brake system.
Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.